A patient in Intellia Therapeutics’ in vivo CRISPR trial for transthyretin amyloidosis (nex‑z) has died, compounding safety concerns that halted dosing in two Phase 3 studies. Intellia reported the hospitalization and subsequent death of a man in his early 80s after grade 4 liver enzyme elevations and bilirubin increases; the company and FDA have placed MAGNITUDE/MAGNITUDE‑2 on hold while investigators probe liver‑related events. Intellia CEO John Leonard said the firm is increasing early post‑dose lab monitoring and investigating patient exclusion criteria; outside analysts, including Guggenheim, warned the adverse events could limit commercial potential. The company and regulator are now focused on mechanistic work and risk‑mitigation before any resumption of dosing.